Showing papers in "International Review of Mechanical Engineering-IREME in 2018"

Fatigue Analysis of Syme’s Prosthesis

Abstract: In this work, the fatigue strength of the Syme’s prosthetic socket is investigated numerically and theoretically with the aim of knowing the resistance of the proposed material of the Syme’s socket to the repeated loads that occurring during locomotion of amputee One proposed laminate for manufacturing the Syme’s prosthetic socket used 4-layers of woven carbon fibre cloth ,6-layers perlon fibre and acrylic resin The layup was (2-P + 1-C + 1- P + 2-C + 1- P+ 1-C + 2-P) The geometric shape of the socket was built using 3D scan for obtaining the real shape of the socket It was noted theoretically and numerically that the maximum principal stresses lay at the bottom fillet of the cutout in the lateral side Also, it was found that the proposed material has the ability to resist the repeated stresses The results of fatigue analysis showed that the minimum value of the fatigue safety factor was equal to 4637 It can be concluded that fatigue strength is inversely proportional to the stresses that applied on the socket, whereas the stresses significantly depend on the applied force, radius of circular section, cutout angle and thickness for the prosthetic socket in the theoretical part

Quality Assurance During Milling of Precision Elements of Machines Components with Ceramic Cutting Tools

Abstract: The article considers matters related to the problems that arise during machining of mating surfaces and bed shears by fine milling with tools equipped with ceramic cutting bits on the basis of the analysis of the surface layer quality requirements and current quality assurance technologies. Research results have shown that one of the quality improvement methods during fine milling of machine component mating surfaces and bed shears is the determination of operability of tools equipped with replaceable ceramic cutting bits.

Multi-Objective Optimization in End Milling Process of ASSAB XW-42 Tool Steel with Cryogenic Coolant Using Grey Fuzzy Logic and Backpropagation Neural Network-Genetic Algorithm (BPNN-GA) Approaches

Abstract: This study investigates the prediction and optimization of multiple performance characteristics in the end milling process of ASSAB XW-42 tool steel, i.e., surface roughness (SR), tool flank wear (VB) and material removal rate (MRR). The quality characteristics of SR and VB was the smaller the better, while MRR was the larger the better. Three methods, namely grey fuzzy logic, back propagation neural network (BPNN) and genetic algorithm (GA), were separately applied. The experimental studies were conducted by varying the end milling process parameters (cutting speed, feed rate and axial depth of cut) and liquid nitrogen cooling flow rate. Grey fuzzy logic was used to obtain a rough estimation of the optimum end milling parameters. The influences of end milling parameters on multiple performance characteristics were determined by using percent contributions. BPNN architecture was determined to predict the multiple performance characteristics. GA method was then applied to determine the optimum end milling parameters. The results of confirmation experiments showed a good agreement with the predicted responses.

Failure Modes and Effects Analysis (FMEA) of Computerized Numerical Control (CNC) Turning Center

Abstract: The intensity growth of manufacturing industry in India is increasing the demand of CNC turning centers. The producers of CNC turning centers are trying to fulfil this demand. The quality and reliability of such CNC turning centers is critical for manufacturers and users to meet the market demand. In this context, it is required to identify the potential failures and minimize their occurrence probability. Failure modes and effects analysis (FMEA) is a robust methodology used to study the risk and reliability of various systems. In this paper, FMEA methodology is used to analyze the risk involved in the operation of CNC turning centers. The objective of the analysis was to identify critical failure modes, components and sub-systems. The study uses field failure data from more than 50 CNC turning centers and more than five industrial experts. FMEA results are further compared to the failure rates obtained from the field failure data. The results of the FMEA analysis are useful for system reliability improvement and optimizing maintenance. Electrical and electronic components have higher failure rates compared to mechanical components. CNCS, MT, XZAS, HS, ChS and SS are found to be critical sub-systems.

Aerodynamics Analisys of the Wingtip Fence Effect on UAV Wing

Abstract: Winglets have an important effect in the use of aircraft and of unmanned aerial vehicle (UAV). The expected effect in winglet usage is the increase of the lift coefficient and the decrease of the drag coefficient. These aspects play a very important role in determining aerodynamic performance. Many researches have been done in order to determine the most effective winglet designs to further explore the effects on aircraft and unmanned aerial vehicle (UAV). Based on that fact, in this study the use of winglet on UAV is discussed. This research has been conducted using a simulation software with turbulent model k-ω SST. The freestream velocity used is 10 m / s (Re=2.3 × 104) with an angle of attack (α) = 0o, 2o, 4o, 6o, 8o, 10o,12o, 15o, 16o, 17o and 19o. Model specimens are airfoils Eppler 562 with and without winglet. Winglet used in this study are wingtip fences with forward and rearward configuration. From the research, it has been found that the addition of winglet can minimize vorticity magnitude behind the wing especially forward wingtip fence. Forward wingtip fence results in a smaller vorticity area than plain wing and rearward wingtip fence although the vorticities increase with the increase of the angles of attack. In addition, the forward wingtip fence can prevent the formation of tip vortex better than the rearward one.

Research of High-Level Control System for Centrifuge Engine

Abstract: Complex centrifuge stands or other complex machines with an electrical motor require a complex control system. As a rule, control systems implemented as physical devices or modules are not replaceable or scalable while programmable control systems can be easily replaced or updated. This paper discusses the black-box electrical motor scheme of interaction based on computer-aided control system.

Design of Motion Control Using Proportional Integral Derivative for UNUSAITS AUV

Abstract: Robotics technology for the defense of a country today is a necessity. One of such defense technologies is an unmanned underwater vehicle or Autonomous Underwater Vehicle (AUV). It is a type of underwater robots operated for underwater exploration or underwater defense system equipment. AUV is controlled and able to move with six degrees of freedom (6-DOF). To control AUV requires a motion control system to move as expected. In this research, the motion control system was developed by applying a linear 6-DOF model to UNUSAITS AUV, resulted from linearization of the nonlinear model with 6-DOF, that is, surge, sway, heave, roll, pitch and yaw with Proportional Integral Derivative (PID) method. Specifically, this study is a make comparison the simulation between result of PID method and those of Proportional control system without integral and derivative was made. The contribution of this paper is numeric study regarding the performance of PID compared to proportional applied to AUV linear model. The simulation results show that the PID method could be used as the motion control system of the linear model 6-DOF with an error of 0.4 % - 13% and globally asymthotically stable with analysis of stability using Lyapunov method, whereas the proportional controller still had a considerably significant error.

Thermal Performances Comparison in Various Types of Trapezoidal Corrugated Channel Using Nanofluids

Abstract: Combining a corrugated channel with nanofluids technologies can improve thermal performance and it can lead to more compact heat exchangers. A numerical study of thermal performance and heat transfer due to the turbulent flow of nanofluids through different configurations of trapezoidal corrugated channels has been investigated. Finite Volume Method (FVM) has been used for the discretization of the governing equations and computations have been performed under constant heat flux over a Reynolds numbers of 10,000-30,000. In order to investigate the impact of nanoparticles on heat transfer and fluid flow, four types of nanoparticles (Al2O3, CuO, SiO2 and ZnO) with varying volume fractions and particle diameter have been utilized in this study. It has been carried out for 0-8% nanoparticle volume fractions with 20-80nm particle diameters. Simulation results show that the corrugation profile has a significant impact on thermal performance compared to a straight profile. Furthermore, by adopting new channel geometries, heat transfer enhancement can be improved to approximately 2.3-3.7 times that of straight channels. Also, the values of Nu have been increased with the increase of Re and nanoparticle volume fraction, and with the decline of the particle diameter. For all the studied forms, the nozzle rib configuration of the trapezoidal corrugated channel achieved a maximum PEC of 2.95 at a volume fraction 0.08 and Re=10000.

Physical and Thermal Properties of Cellulose Nanofibers (CNF) Extracted from Agave Cantala Fibers Using Chemical-Ultrasonic Treatment

Abstract: Cellulose nanofibers (CNF) have been extracted from agave cantala fibers by using chemical-ultrasonic treatment. The raw fibers have been subjected to alkali and bleaching treatments followed by acid-hydrolysis. The characteristics of cantala fibers such as their morphology through scaning electron microscope (SEM), Transmission electron micrsoscop (TEM), fourier transform analysis (FTIR), x-ray diffraction (XRD) and thermogravimetric analysis (TGA) have been analyzed. The CNF extracted from cantala fiber had uniform diameters of 45-50 nm with 800-2000 nm in lengths. Change in the FTIR spectra of CNF indicated that hemicellulose and lignin were significantly removed during chemical treatment. The crystallinity index of CNF increased when chemical treatment followed by optimum-time ultrasonic treatment was applied. The TGA discovered that CNF was stable until 271 oC. Based on the properties, the CNF would be suitable for reinforcement of nanocomposites.

Wind tunnel experiment of UTM-LST generic light aircraft model with external store

Abstract: This paper discusses the impact of the external store on the aerodynamic performance of the light aircraft model in the subsonic region. Light aircrafts are commonly used for pilots training, survey, leisure and transportation. To date, there have been a lot of small aircrafts used for strategic purposes where an external store, either external fuel storage or armament, has been installed on its wing. Examples of such aircraft are KAI-KA1, A29 Super Tucano, and Beechcraft AT-6. Therefore, it is important to study the effect of this external store installation on the aerodynamic characteristics of a small aircraft. An available light aircraft model of UTM Low speed wind tunnel (UTM-LST) has been modified so that a generic external store can be mounted on the lower surface of the wing. Two set of experiments were carried out on the model which were; experimental with an external store followed by experimental without external store as a benchmark of tested configuration. The experiments were conducted at two different speeds of 26 and 39 m / s that correspond to Reynolds numbers 0.4 × 106 and 0.6 × 106respectively. Three measurement techniques were employed on each configuration. The first measurement was the 6 component forces and moments measurement technique. The second technique was the pressure measurement on the wing, and the final test was the tufts flow visualization. The result of steady balance indicated that the external store has no effect on the coefficient of lift at low attack angle. However, it showed that there was a reduction of lift coefficient by 2% at higher angle of attack. The data showed that the coefficient of drag increases by 4% when the external is installed. Surprisingly, the installation of the store has insignificant effects on the pitching moment coefficient. An interesting feature observed from surface pressure studies where, the results showed that the pressure coefficient increased when the external is mounted on the wing at a low angle of attack. Such changes, however, do not occur at high angle of attack.

Design, Simulation, and Control of an Omnidirectional Mobile Robot

Abstract: Nowadays, the design phase of any mechatronic system is mandatory before the implementation and the construction of a prototype. In the design phase, it is crucial to minimize failures, without under-dimensioning, any drive system in the desired prototype, using different simulation tools to test the proposed design under varied conditions.In this paper, the design, the simulation, and the control of a holonomic or omnidirectional mobile robot are presented. The design approach consists of a mathematically based method. The obtained model is an approach of the studied mobile robot, that allows an approach to the system’s behaviour, to a testing platform, and to a simulator for the desired robot, including most of the innerrobot’s interactions. The main contributions of this paper are the presentation and the study case of a proposed structured methodology for the study of any mechatronic-robotic system.

Experimental Investigations on Flexural and Fracture Behaviors of Flax Fiber Reinforced Sandwich Panels

Abstract: Natural fiber reinforced sandwich composites have been of keen interests to researchers as a result of their low cost, moderately good mechanical properties, and biodegradability. The main attention of the present work lies on the eco-friendly honeycomb structures for sandwich panels. This paper investigates the mechanical characteristics of flexural and fracture strengths of the sandwich panels involving polypropylene as its core and treated flax fabric fiber reinforced polymer matrix composites as face sheets. Taguchi's design of experiments is implemented in the experimental analysis. The influence of fabric orientation and surface treatment on the properties is reconnoitered. Analysis of Variance (ANOVA) is employed to study the influences of different parameters on flexural and fracture strengths of sandwich panels.

Stress Corrosion Cracking at ASTM A36 Plate with Varied Grain Orientation

Abstract: Stress corrosion cracking (SCC) has been acknowledged as a trigger phenomenon which can cause a failure especially in welded pipeline installations. By the name, three factors must be involved in SCC failure: stress, corrosive environment and an initial crack. This article observes the effect of grain orientation to the SCC failure in ASTM A36 plate. The results show that with lower grain orientation the precracked plate withstands longer in a certain corrosive surroundings and stress load. From microstructure observation the finer grains in lower orientation are believed to increase the SCC resilience. The microstructure at fracture region shows that the lower orientation tends to develop intergranular crack growth whilst at higher orientation transgranular is exhibited. This phenomenon also explains why the lower grain orientation can hold SCC failure longer.

The Effect of Compressor Speed Variation and Vapor Injection on the Performance of Modified Refrigeration System

Abstract: This work presents an experimental and numerical investigation of vapor compression refrigeration system performance with variable speed compressor and vapor injection. A test rig of 5 ton capacity split air conditioner equipped, with frequency inverter to control the speed of scroll type compressor, and a secondary capillary tube to expand the refrigerant in the vapor injection circuit are used to conduct the experimental work. Three different vapor injection mass ratios (2, 3, and 4%) are investigated with variable compression speed for frequency range from 35 to 60 Hz. TRNSYS-16 is the software is used to simulate a single zone building conditioned with the modified split air conditioner. The results showed that, the reduction of the compressor speed to the frequency of 35Hz leads to an improvement of the COP by 36% and reduces the power consumption by 18%, compared to the conventional refrigeration system. The usage of the vapour injection with variable speed compressor has improved the COP of the modified system by 47% at 35 Hz and 2% vapour injection ratio. The average improvement in cycle capacity at different compressor speeds is about 24.6%, 28.77% and 34.28% respectively for the vapor injection ratios of 2%, 3& and 4%. It was observed that the reduction of compression speed can extend the compressor lifetime by reducing the ON/OFF cycle of the system at a speed of 35Hz and 2% vapor injection by 17.3%, compared to the conventional system. While at a speed of 60Hz, the ON/OFF cycle has increased by 9.3 and 12% for 2% and 4% injection ratios, respectively. The comparison between the numerical and experimental results of the modified system with vapor injection ratio 2% and 35 Hz compressor speed has displayed an increase in the numerical results around 2.57% for COP, 5.8% for cooling capacity and 5.68% for compressor power consumption.

Mechanical Response of Short Fiber Reinforced Fly Ash Based Geopolymer Composites

Abstract: The requirement for environmentally friendly construction materials for sustainable development is nowadays an important issue and the geopolymer technology provides a good solution to replace, as binder, the ordinary cement materials for green building. Fly ash, an industrial by-product currently disposed of as waste, can be used as feedstock for geopolymers with an excellent greenness. In order to preserve the eco-friendly nature of the fly ash based geopolymer and enhance the mechanical properties that represent a weak point of the cementitious materials, limiting their application fields, a new fly ash based geopolymer composite was introduced. For this purpose, inorganic, organic and natural short fibers, i.e. E-glass, aramid and hemp respectively, were considered as reinforcement. The mechanical response of these composites under quasi-static and dynamic load conditions was investigated and compared to plain geopolymers, drawing the attention to the hemp reinforced ones, because of their low coast and eco-friendly nature.

Simulation and Experimental Validation of Slider Displacement in Slider Crank Mechanism with Connecting Rod Tolerance and Joint Clearance

Abstract: In this paper, a simulated analysis and an experimental validation of slider displacement in a slider crank mechanism have been done. Link tolerance and joint clearance have been considered for the analysis since these factors influence robustness of mechanism. A slider crank mechanism has been designed by specifying tolerance of connecting rod and joint clearances at slider-connecting rod and crank–connecting rod joints. Slider displacement simulations have been performed using ADAMS/View software. In order to understand the effect of speed on slider displacement, simulations have been performed at three crank speeds. All simulation results have been validated by performing experiments on the fabricated setup. It has also been observed that the joint clearance influenced variation in slider displacement is higher than the link tolerance and the speed variation. Thus, the robustly designed mechanism could be analyzed by simulating in ADAMS/View by varying the design parameters within specified ranges than by performing experimentation on fabricated setup.

Atmospheric-Pressure Annealing Effect on the Impact Fracture Toughness of Injection-Molded Zeolite-HDPE Composite

Abstract: This study focuses on an investigation of the fracture behavior of zeolite-HDPE composites after annealing treatment under atmospheric pressure. Annealing processes were carried out at various holding time (12, 24, 36, and 48 hours). The fracture toughness of composites was investigated based on the essential work of fracture (EWF) concept, and the surface morphology of composite was evaluated using scanning electron microscope (SEM). The results show that the essential work of the fracture increases with the increase of the holding time of annealing process up to 36 hours. However, all tested materials exhibit negative values in term of non-essential fracture work. The outer plastic deformation zone cannot be observed around the ligaments of the fracture propagation pathway on the surface of the broken sample. Thus, all the fracture energy was used to create a new fracture surface in the inner fracture process zone.

Sonication Assisted Synthesis of Biocomposite from Starch/Nanoclay and its Properties

Abstract: The potential development of the biodegradable plastic packaging technology in Indonesia is enormous because Indonesia has abundant biodiversity of agricultural and marine products to be developed into polymers. Cassava starch as the matrix biocomposite in packaging manufacturer has a great potential because in Indonesia there are various starch-producing plants. The research objective was to determine the influence of the sonication process on the strength of biocomposite starch reinforced by nanoclay. The method was a synthesis of biocomposite using a casting procedure. The sonication process of 5% (b/b) nanoclay in solution was conducted in 15, 30, 45, and 60 min using the ultrasonic homogenizer and then poured into the mold. The mechanical properties were measured using a tensile test machine with a maximum load of 50 N. The results showed that the duration of the sonication process affects the tensile strength of biocomposite starch reinforced by nanoclay. This result was demonstrated by the term of the sonication process by 15, 30, 45, and 60 minutes resulting in biocomposites strength and elongation of 11.79, 14.77, 20.52, 28.01 MPa, respectively. It showed that the duration of the sonication process of more than or equal to 45 minutes enhances both tensile strength and surface smoothness.

Concept of Gear Synthesis Based on Assignment of Instant Contact Areas for Loaded Teeth

Abstract: Objects of investigation are gears with point system of meshing, that is, with localized tooth contact. The purpose of investigation is the development of scientific fundamentals for a new method of optimization synthesis of plane and spatial gearing; the method basing on assignment of the shape, dimensions and location of instant areas of tooth contact along assigned and synthesized meshing lines. The purpose of synthesis is to determine parameters of contact point motion along the meshing line, parameters of contact areas and tooth surfaces for which the circumferential load becomes maximal. The synthesis is started with revealing the areas (within a fixed coordinate system) with good, acceptable and inacceptable conditions for tooth contact. This work is considered to be the continuation of M. L. Novikov method for generation of conjugate meshing. The manuscript involves the review of publications on methods for synthesis of meshing; statement of laws of mechanics and scientific knowledge applied when developing the concept of synthesis. It is shown that in Wildhaber-Novikov gears two convex solids are contacting with each other rather than a convex solid with the concave one. Fundamentals of the proposed concept are stated; the plan on implementation of the proposed concept of synthesis and design is presented; basic problems of initial stages of work are listed; and approaches to their solution are stated.

The Method for Determining the Relative Positions of the Operator's Arm for Master-Slave Teleoperation of Anthropomorphic Manipulator

Abstract: The aim of the article is to increase the accuracy of the capture of the operator's arm for the master-slave teleoperation anthropomorphic manipulator. As the master device, a mechanical system is considered, the links of which are parallel to the operator's arm. The Cartesian coordinates of the shoulder joint, carpal joint and the operator's hand, are determined by solving the direct kinematics problem through the Denavite-Hartenberg representation. A new geometrical method for solving the inverse kinematics problem for determining the Cartesian coordinates of the elbow joint is proposed. The proposed method provides an accurate determining of the position of the operator's arm for the considered master device. The low computational complexity of the geometric method makes it possible to use it in real-time systems. The value of the research is determined by the urgency of the problem of the accuracy of master-slave teleoperation.

Crawler Crane Overturning Analysis for the Case of Boom Luffing Motion

Abstract: This is a research about crawler cranes operating with full load in order to determine the risk of overturning. The case of crane motion is boom luffing. The method of analysis is the comparison of results gained through modeling and simulation and experimental measurements. It is well known that boom motion at crawler cranes is followed by heavy oscillations mainly caused by load swinging, which passes to the boom and other parts of the crane. This occurrence can create problems with stability, load drop and crane overturning. The main focus is the study of dynamic stability, overturning moment and forces in some parts of the crane. Overturning moment is the main stability parameter in these cranes and depends on mass as well as on geometric and kinematic parameters. This moment will be compared to the static moment, and the exact position of the boom will be searched where overturning can happen. The results gained from the simulations will be presented in graphical form. Also, they will be compared to the results from experimental measurements.